Geckodrive G540 User manual

G540 MANUAL
MULTIAXIS STEP MOTOR DRIVE

PRODUCT DIMENSIONS
PHYSICAL AND ELECTRICAL RATINGS
Minimum
Maximum
Units
Supply Voltage
18
50
VDC
Motor Current
0
3.5
A
Power Dissipation
1
13
W
Short Circuit Trip
14
A
Temperature
0
70
°C
Humidity
0
95
%
Motor Inductance
1
30
mH
Input Frequency
0
200
kHz
Step Pulse “0” Time
2
uS
Step Pulse “1” Time
1
uS
Direction Setup
(Before step rising edge)
200
nS
Direction Setup
(Hold after pulse rising edge)
200
nS
Signal Voltage
3.3
5
VDC
Weight
8.8
oz.
Charge Pump Frequency
10
kHz

Thank you for choosing to purchase the G540 4-Axis Drive System. If you are dissatisfied with it for any reason at all within 90
days of its purchase date, you may return it for a full refund provided it is cosmetically unmarred and undamaged electrically in
any way. Geckodrive Inc. fully warranties the G540 against workmanship defects for 3 years after its purchase date.
PLEASE READ FIRST BEFORE USING THE G540
Before beginning, be sure to have a suitable step motor, a DC power supply suitable for the motor and a current set resistor.
The motor’s rated phase current must be between 0 Amps and 3.5 Amps. Using a motor with a higher current rating will cause a
proportional loss in torque, meaning a 5A motor will get 3.5/5 (70%) of its maximum torque. The power supply voltage must be
determined by the inductance equation listed later or be between 4 times and 20 times the motor’s rated voltage. The current
set resistor may be a 1/4 Watt, 5% part. Finally have a STEP and DIRECTION pulse source available.
STEP 1: CONNECT POWER
Connect your power supply positive to TERMINAL 11 and negative to TERMINAL 12. The power supply voltage is determined by
multiplying the square root of the motor’s inductance by 32, as in the example below for a 2mH rated motor:
32 * (√2) = 45VDC
Be sure that your power supply is turned OFF when connecting or disconnecting it from the G540. Failure to do so may result in
physical damage to the connectors.
CAUTION! Never put a switch on the DC side of the power supply! This will damage, if not destroy, your drive due to a current
inrush when the switch is first thrown.
CAUTION! Power supply voltage in excess of 50 VDC will damage the G540.
Turn the power supply on and make sure that a red LED comes on. Once you have verified that the drive lights up turn your
power supply off before continuing.
STEP 2: INSERT E-STOP OR JUMPER
The G540 is designed to fault unless there is a normally closed switch (functionally identical to a jumper wire) between
TERMINAL 10 and TERMINAL 12 on the 12-PIN TERMINAL BLOCK. Without TERMINAL 10 shorted to ground the G540 will
remain disengaged to the motors and will not respond to commands. The red LED will be illuminated if there is no jumper
connecting these two terminals.
STEP 3: DISABLE CHARGE PUMP
The G540 has a switch allowing you to disable the charge pump feature, which makes it possible to verify the G540 works
without having to have your DB25 cable plugged in. The switch is located near the 12-PIN TERMINAL STRIP on the top of the
drive. Flip the switch to DISABLE and apply power to the G540; you should have a green LED lit indicating that setup is
successful thus far.
STEP 4: CONNECT MOTORS
Wire your motors to the included DB9 solder cup and secure the backshell connectors. If your motors are rated below 3.5A you
must use a current set resistor across PIN 1 and PIN 5. The resistor is calculated by taking the current in amps and multiplying
by 1000. If your motor is rated at 2.8A per phase you will have to use a 2.8K 5% 1/4W resistor. If your motor is rated at 3.5A or
above you can safely not use a current set resistor; however, your G540 will not go into current standby mode which will result
in increased motor heating.
At this point you should have holding torque on the motors and a green LED lit. If you do not then the motor is wired incorrectly
or is damaged.

STEP 5: CONNECT DB25 CABLE
If you have holding torque and a green LED you can plug in your DB25 straight through cable to the G540 and your computer.
Use the pinout on page 7 to set up your program’s output pins or load the G540 XML configuration file from the G540 product
page on the Geckodrive website.
Your step pulse width must be at least 2uS wide and the pulse polarity for the step and direction signals are ACTIVE HIGH.
STEP 6: TEST FUNCTIONS
After you configure your CNC program it is time to test the G540 for functionality. You should be able to move all axes at this
time.
STEP 7: ADJUST TRIMPOT
The G540 is composed of four individual G250 motor controls, each of which has a designated pin outputting the smoothness
adjust trimpot to the G540 motherboard. In your CNC program set the axis being adjusted to move at 2 revolutions per second
and use a screwdriver to turn the trimpot in the ADJUST hole on the top of the drive. The trimpot has 270 degrees of motion
and will have an audible “sweet spot” when it is in proper position. This position will change with each motor so be sure to
readjust if you change motors.
STEP 8: OPTIONAL CONNECTIONS
The following connections are completely optional and are not required to make the G540 operate.
INPUTS: The G540 has four general purpose inputs called INPUT 1, INPUT 2, INPUT 3 and INPUT 4 on the MAIN
TERMINAL BLOCK. They are at POSITION 1, POSITION 2, POSITION 3 and POSITION 4 respectively on the terminal
block. These inputs may be used as limit switches or for any other purpose. SPST switches can be used with these
inputs. One end of the switch goes to the input, the other end of the switch goes to ground (POSITION 12).
OUTPUTS: The G540 has two general purpose outputs called OUTPUT 1 and OUTPUT 2 on the MAIN TERMINAL
BLOCK. They are at POSITION 5 and POSITION 6 respectively on the terminal block. These outputs may be used to
drive relay coils or for any other purpose. The outputs are rated at 1A and 50VDC maximum. Connect one end of the
load to the output and connect the other end of the load to a positive DC voltage. This voltage may be the G540
power supply or it may be a separate power supply having a different voltage.
ANALOG OUTPUT: This is a 0V to +10V opto-isolated analog output intended for use with VFD drives. VFD OUT goes
to 0VDC while the G540 is disabled. Connect VFD GND, VFD OUT and VFD +10V to the VFD drive inputs. Make sure the
VFD drive positive voltage does not exceed +12VDC. Do not short VFD OUT to any other terminal. Do not reverse
polarity to VFD GND and VFD +10V or the G540 may be damaged.
CHARGE PUMP: The G540 is equipped with a charge pump (watchdog timer) that disables the drive without a 10 kHz
signal on pin 16 of the DB25 port. You can enable this by reversing what was done in STEP 3 and making sure that
your parallel port is set to EPP mode. To do this, go into BIOS and set your parallel port to either “EPP” or
“Send/Receive”; most parallel cards are set to ECP or “Send Only” by default.

DISCLAIMER
CERTAIN APPLICATIONS USING POWER PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY OR SEVERE
DAMAGE TO PROPERTY. GECKODRIVE INC. PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR
USE IN LIFE-SUPPORT DEVICES OR OTHER CRITICAL APPLICATIONS. INCLUSION OF GECKODRIVE INC. PRODUCTS IN SUCH
APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE PURCHASER’S OWN RISK
In order to minimize risks associated with the purchaser’s application, adequate design and operating safeguards must be
provided by the purchaser to minimize inherent or procedural hazards. GECKODRIVE INC. assumes no liability for applications
assistance or the purchaser’s product design. GECKODRIVE INC. does not warrant or represent that any license, either express or
implied, is granted under any patent right, copyright or other intellectual property right of GECKODRIVE INC.
MANUAL CHANGE LOG
DATE
CHANGES MADE
3/1/2012
New manual format published
3/5/2012
G540 Revision 8 released
1/17/2017
Updated manual format and address change

TROUBLESHOOTING
Generally speaking, there are only a few reasons why the G540 will not function as expected. The most common are listed
below. To help in troubleshooting in the field you may want to view our troubleshooting video on the G540 product page at
www.geckodrive.com.
PROBLEM: G540 UNRESPONSIVE (RED LED LIT CONSTANTLY)
SOLUTION: This is the most common fault and can be caused by several problems. First, double check that a jumper
wire or normally closed switch is present between PIN 10 and PIN 12 on the 12 POSITION TERMINAL BLOCK. Next, turn the
CHARGE PUMP SWITCH to the OFF position; if the green LED comes on then there is a problem with your CNC program not
putting out a charge pump signal on PIN 16. If those do not work, check the motor for holding torque; if you do not have
holding torque move on to the next section.
PROBLEM: NO MOTOR HOLDING TORQUE
SOLUTION: Verify that your motor is connected to the G540 with the DB9 connector and that it is wired as it says in
the motor’s datasheet. Check the LED indicators to verify that power is being applied to the G540. Lastly, make sure that you
have an appropriately sized current set resistor. If there is not one present or it is grossly undersized you may have burned out
your motor and it could be shorted internally.
PROBLEM: NO LEDS LIT
SOLUTION: Verify that the power supply is plugged in correctly to the 12-PIN TERMINAL BLOCK. If it is and power is
applied with no LEDs being lit up, you have most likely had the fuse blow open. To check the fuse you must first remove the
cover. The fuse is located by the 12-PIN TERMINAL BLOCK on the underside of the motherboard; you can pull the motherboard
off of the G250 drives to access it. Next, use an ohmmeter to check for continuity on the fuse, which looks like a green 1/4W
resistor. If the fuse it destroyed you may contact Geckodrive for replacement fuses or order spares online with part number
F2318-ND from www.digikey.com.
PROBLEM: INPUTS OR OUTPUTS NOT WORKING
SOLUTION: This problem is most often caused by a problem with the parallel port or the parallel cable. Use an
ohmmeter to verify that your cable is a straight through cable and not a crossover or a printer cable. Next, go into BIOS and
make sure that your parallel port is set to EPP or “Send/Receive” mode. If your parallel port is on your motherboard and is not a
PCI card then the problem could be that it is incapable of EPP operation. Use a PCI parallel card and see if the problem persists.
PROBLEM: G540 GETS HOT
SOLUTION: The G540, being a stepper drive, is meant to get warm. While operating at its maximums the G540 can get
up to 70C (158F) comfortably; heatsinking is mandatory if the temperature gets above that range. On the Geckodrive website is
a document titled “G540 Heatsink Experiment” that discusses issues of overheating. If the G540 is in a control cabinet or an
area with limited airflow it is required to put an intake and exhaust fan in the enclosure. Please read the cited document if you
have further questions.
IMPORTANT!
If your drive will not come out of fault or is not acting normally, please return it for evaluation. A return form can be found at
www.geckodrive.com under the “Support” tab at the top. All repairs and evaluations are performed free of charge and include
return shipping while under warranty.

DB 25 PINOUT DB9 PINOUT
MAIN TERMINAL BLOCK PINOUT
IMPORTANT WIRING NOTES
1.) Always verify that your DB25 cable is a straight through cable, not a crossover. This can be done by using an
ohmmeter to test continuity between all pins.
2.) Do not allow the current set resistor to touch pins 2, 3, or 4 on the DB9 cable. This will set off a FAULT condition in the
G540.
3.) Do not use wire plugs for the main terminal block. Only put stranded wire with a gauge range of 14 –24 to make
proper contact and not stress any terminals.
4.) The only required connections for the G540 to run are a power supply and a normally closed emergency stop. If you
get a fault at any time that will not clear, you can safely disconnect all wires but these and get a green LED with the
charge pump turned off.
Pin Number
Minimum
1
OUTPUT 2
2
X-AXIS STEP
3
X-AXIS DIRECTION
4
Y-AXIS STEP
5
Y-AXIS DIRECTION
6
Z-AXIS STEP
7
Z-AXIS DIRECTION
8
A-AXIS STEP
9
A-AXIS DIRECTION
10
INPUT 1
11
INPUT 2
12
INPUT 3
13
INPUT 4
14
VFD PWM (50 Hz)
15
FAULT (input to PC)
16
CHARGE PUMP (>10 kHz)
17
OUTPUT 1
18
GND
19
GND
20
GND
21
GND
22
GND
23
GND
24
GND
25
GND
Pin Number
Minimum
1
CURRENT SET RESISTOR
2
N/C
3
N/C
4
N/C
5
CURRENT SET RESISTOR
6
PHASE B MOTOR WIRE
7
PHASE /B MOTOR WIRE
8
PHASE A MOTOR WIRE
9
PHASE /A MOTOR WIRE
Pin Number
Minimum
1
INPUT 1 (DB25 PIN 10)
2
INPUT 2 (DB25 PIN 11)
3
INPUT 3 (DB25 PIN 12)
4
INPUT 4 (DB25 PIN 13)
5
OUTPUT 1 (DB25 PIN 17)
6
OUTPUT 2 (DB25 PIN 1)
7
VFD GROUND
8
VFD OUTPUT
9
VFD +10VDC
10
DISABLE INPUT (E-STOP)
11
SUPPLY +18 –50VDC
12
POWER SUPPLY GND

Sample Wiring Diagram
Please note that all connections shows above are optional except for the power supply and E-Stop switch. A few frequently
asked questions for wiring are below:
How do I use the OUTPUTs with a relay?
The OUTPUTs on the G540 are functionally single-pole single-throw switches to GND. When the corresponding pin on the DB25
is activated it will allow current to flow, functionally shorting the OUTPUT and TERMINAL 12 (GND). The voltage can be the
same as your G540 power supply or you can use a dedicated supply just for the OUTPUTs. Make sure the GND lines are tied
together at the same point if you use a secondary supply.
Can I put more than one input into a terminal?
Yes, but you will lose the ability to home if you double-up your inputs. If you are using these as limit switches you can put more
than one in each terminal. If they are NO switches then you would want to wire them in parallel; if they are NC switches you
would want to wire then in series.
How can I add a fifth axis?
There is no simple way to add a fifth axis to the G540 without external hardware. You may need to use a third-party motion
controller to allow you to have coordinated STEP and DIRECTION output to a fifth axis drive, such as the G251X.

G540 CUTOUT DIAGRAM

This drawing is to scale. Use it as a guide for panel mounting your G540.